ISP-operated servers alter search results, researchers claim

Search engine requests are being altered to redirect users to specific websites in a "stealthy" system that benefits advertisers, US researchers have claimed.

"Malicious servers" operated by internet service providers (ISPs) redirect users to websites relating to the information they have searched for using search engines available in browsers' address bars, the Microsoft and University of New York researchers said.

Online advertising companies are profiting from the system which "inserts several rounds of redirection before eventually directing the user to her destination," the researchers said in a study (8-page/286KB PDF).

"These companies get paid when their advertisement links are clicked by users. The extra rounds of inserted redirection are used to generate clicks, as if they are from a large number of real users," they said.

"In addition, we noticed that this type of modification is extremely stealthy. It only intercepts and redirects if the search queries are generated from the address bar of web browsers. Clearly, only intercepting the queries from the address bar reduces the risk of exposing the malicious servers," they said. "Interestingly, most malicious servers that we have discovered belong to this category."

The malicious servers are also altering search engine requests in other ways, including changing the links that appear alongside results and adverts that accompany those results, the researchers said. Almost 2 per cent of US internet users are affected by alterations made through the malicious servers, they said.

"In total, we discover 349 servers as malicious, that is, as modifying content inflight, and more than 1.9 per cent of all US clients are affected by these malicious servers," the study said.

Intercepting communications is prohibited under the US Wiretap Act. In the UK a similar law, the Regulation of Investigatory Powers Act (RIPA), also prohibits the interception of communications without a user's knowledge or permission in most cases.

Under RIPA, law enforcement agencies, including the police and MI5, can tap phone, internet or email communications to protect the UK's national security interests, prevent and detect terrorism and serious crime or to safeguard the UK's economic well-being.

Telecoms firms are allowed to unintentionally intercept communications in line with RIPA if the interception "takes place for purposes connected with the provision or operation of that service or with the enforcement, in relation to that service, of any enactment relating to the use of postal services or telecommunications services".

The law also states that unlawful interception takes place if a person makes "some or all of the contents of the communication available, while being transmitted, to a person other than the sender or intended recipient of the communication". It also states that interception is illegal on messages stored "in a manner that enables the intended recipient to collect it or otherwise to have access to it".

Unlawful interceptors of communications and those who commission the illegal practice face the risk of prosecution. The law does not give the accused the right to claim the hacking activity was conducted in the public interest.

In May, Parliament changed RIPA so that it is only legal to monitor private communications, even unintentionally, if you have a warrant or if both the sender and recipient of information agree to the monitoring. The law had previously said that you could monitor without a warrant if you had "reasonable grounds" to believe that the parties to the communication had consented to the monitoring.

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